Patch "i2c: rcar: ensure Gen3+ reset does not disturb local targets" has been added to the 6.1-stable tree

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This is a note to let you know that I've just added the patch titled

    i2c: rcar: ensure Gen3+ reset does not disturb local targets

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i2c-rcar-ensure-gen3-reset-does-not-disturb-local-ta.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit f32b7cd0e53970fd1e7e2faf0a994388c8549345
Author: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Date:   Thu Jul 11 10:30:44 2024 +0200

    i2c: rcar: ensure Gen3+ reset does not disturb local targets
    
    [ Upstream commit ea5ea84c9d3570dc06e8fc5ee2273eaa584aa3ac ]
    
    R-Car Gen3+ needs a reset before every controller transfer. That erases
    configuration of a potentially in parallel running local target
    instance. To avoid this disruption, avoid controller transfers if a
    local target is running. Also, disable SMBusHostNotify because it
    requires being a controller and local target at the same time.
    
    Fixes: 3b770017b03a ("i2c: rcar: handle RXDMA HW behaviour on Gen3")
    Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 975bba5e4a344..c7a51e0876cf5 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -824,6 +824,10 @@ static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
 {
 	int ret;
 
+	/* Don't reset if a slave instance is currently running */
+	if (priv->slave)
+		return -EISCONN;
+
 	ret = reset_control_reset(priv->rstc);
 	if (ret)
 		return ret;
@@ -1114,6 +1118,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	if (of_property_read_bool(dev->of_node, "smbus"))
 		priv->flags |= ID_P_HOST_NOTIFY;
 
+	/* R-Car Gen3+ needs a reset before every transfer */
 	if (priv->devtype >= I2C_RCAR_GEN3) {
 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 		if (IS_ERR(priv->rstc))
@@ -1122,6 +1127,9 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 		ret = reset_control_status(priv->rstc);
 		if (ret < 0)
 			goto out_pm_put;
+
+		/* hard reset disturbs HostNotify local target, so disable it */
+		priv->flags &= ~ID_P_HOST_NOTIFY;
 	}
 
 	ret = platform_get_irq(pdev, 0);




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